There are many known air bag inflator constructions. Some inflator constructions include combustible gas generating material. A known inflator construction includes a combination of stored gas and combustible gas heating material. Upon ignition of the gas heating material, the stored gas is heated, and there is a resulting increase in fluid pressure. The increased fluid pressure ruptures a member to release the stored gas from the inflator for flow into an air bag. The gas flows through discharge openings in a housing of the inflator into the air bag.
The combustible gas heating material may be subject to degradation if exposed to moisture in the ambient atmosphere of the inflator. Accordingly, inflators include some means to block the moisture in the ambient atmosphere from contacting the gas heating material. One means to block the moisture is a metal foil seal adhesively secured to a surface of the inflator housing across the discharge openings. The metal foil seal forms a moisture barrier between the gas heating material inside the inflator and the environment outside the inflator. When the inflator is actuated, the pressure of the gas flowing through the discharge openings ruptures the metal foil seal.